1. Field of the invention
This invention relates to a medical aspirator with automatic valve means and bypass means to move blood and other material without passing the same through the automatic valve means.
2. Description of the Prior Art
The present invention is an improvement over the subject matter of U.S. Pat. No. 4,447,226. This patent is directed to a surgical aspirator which operates automatically to remove a blood clot or other material which stops the suction flow of the aspirator.
Aspirators to remove blood and other matter during operations have been known for many years. However, before the advent of the subject matter of U.S. Pat. No. 4,447,226 there was never any successful fully automatic non-cyclical way of removing blood clots or other large pieces of matter that plugged the nozzle of the system. The matter usually had to be removed by hand which could cost valuable time which may be critical during certain operations.
With the advent of U.S. Pat. No. 4,447,226 the removal of obstructions at the nozzle of an aspirator system was automatic. The stoppage caused the system to reverse and instead of suction being applied at the nozzle, air or oxygen was forced out the nozzle and the obstruction was dislodged. The operation is automatic and the reversal of air can be momentary and many time per minute.
While the invention of U.S. Pat. No. 4,447,226 was a breakthrough in automatic aspirators it has a disadvantage that the blood and other matter sucked from the wound or area of the operation has to pass directly through the automatic valve means. Such structure might be susceptible of blockage or malfunction by blood and matter entering the rotating valve means.
Applicant is also aware of U.S. Pat. No. 3,955,574 for a "Pumping System For Catheter Suction Units." This patent was cited as the primary reference against U.S. Pat. No. 4,447,226 but is easily distinguished in that it is a timer type of system whereas U.S. Pat. No. 4,447,226 is non-cyclical and fully automatic when a stoppage occurred.